Multi-WAN with 8 PPPoE accounts

I have 4 dual NICs in my box and 8 modems. Only 2 PPPoE accounts ever seem to work at one time. And it's random, any 2 work. WAN and OPT7 or OPT2 and OPT5, but not all 8 at the same time. Any ideas? Am I asking too much? Do I report this as a bug?